A conventional LCD driver circuit may comprise a random access memory (RAM) for storing data to be displayed on an LCD panel. The RAM may be supplied by an interface logic, which receives instructions from a set of programming inputs. The RAM may supply the stored data to a latch circuit, which may include a plurality of data latches. A set of shift registers may be coupled to the latch circuit. The conventional LCD driver circuit may also include a control logic and a display timing generator circuit. The control logic and the display timing generator circuit may provide appropriate signals to the latch circuit, the RAM, and the set of shift registers.
A segment driver circuit (i.e., column driver circuit) may be coupled to receive outputs from the latch circuit. The segment driver circuit may include multiple segment drivers equal to the number of columns in the LCD panel. A common driver circuit (i.e., row driver circuit) may be coupled to receive outputs from the shift registers. The common driver circuit may include multiple common drivers equal to the number of rows in the LCD panel. Each of the segment driver and common driver may output a corresponding segment signal or common signal to the LCD panel. Each segment and common signal may represent the data or graphics to be displayed on the LCD panel.
An LCD panel may have hundreds or thousands of pixels that may be energized depending on the voltage located at a junction of one of the rows and one of the columns in the LCD panel. When driving an LCD panel, a multiplex method is typically used where the display dots of the LCD panel may be divided into a number of groups. Each group may be provided with a common electrode, which is usually a row electrode. The common electrodes may be sequentially selected to drive the dots of the group, thereby producing a pattern on the LCD panel.
The above-described conventional LCD driver circuit usually has dedicated common and segment drivers with fixed output drive capability, which may cause one or more of these drivers to be wasted, as well as complicate signal routing in the LCD driver circuit.